whittier



( Modem 0. R. WHITTIER. 2 Sheets-Sheet 1.

ELEVATOR. No. 552,665. Patented Jul 16,1895.

0 L q if E Ill (No Model.) 2 Sheets-Sheet 2.

C. R. WHITTIER. ELEVATOR.

No. 542,665. Patented July 16, 1895.

Untrr'nn STATES ATENT Fries.

CHARLES R. WHITTIER, OF NEW YORK, N. Y.

ELEVATO R.

SPECIFICATION forming part of Letters Patent No. 542,66 5, dated July 16,1895

Application filed March 24, 1894:. Serial No. 504,931. (No model.)

To atZZ whom it may concern:

Be it known that 1, CHARLES R. WHITTIER, a citizen of the United States, residing in the city and county of New York, in the State of New York, have invented a certain new and useful Improvement in Elevators," of which the following is a specification.

The invention relates to the provisions for counterbalancing the ropes by which the elevator is operated. It is of most importance in connection with the elevators used to conveypassengers or freight in high buildings. I will describe the invention as so applied, the elevator being operated by hydraulic power.

It is usual to partially counterbalance the gravity of the car by means of a weight suspended by a' separate rope. The considerable weight of the ropes in being transferred from one side to the other of the overhead sheaves is a disturbing element which becomes of importance as the height of the building and the consequent len th of the ropes are increased. The difiiculty has been recognized and efforts have been made to overcome it by attaching heavy chains to the under side of the elevator or counterweight or byopposing the movement of the piston by the elastic property of compressed airi There are objections to both these methods. I have discovered that the counterbalancing of the weight of the ropes may be attained with great perfection by means of air imprisoned in the cylinderin just sufficient quanti ties to attain a neutral condition when the piston has traversed about one-third of its path in the direction to elevate the car, and shall be in a condition of compressed air or a plenum during the period while the car is at the mid-height and near the top of its course, and subject to a pressure below that of the external atmosphere, a partial vacuum, when the piston is traversing about a third of its course with the car near the bottom.

The accompanying drawings form a part of this specification and represent what 1 consider the best means of carrying out the invention as applied to an elevator of the hydraulic-pushing type. The height of the in elevation.

tion of a portion, showing a modification. Figs. 3, 4, and 5 are side elevations showing the entire apparatus in either form on a smaller scale. Fig. 3 shows the car in its lowest, Fig. 4 in its intermediate, and Fig. 5 in its highest, position. Fig. 6 is a diagram indicating the amount of the force which requires to be balanced at difierent points in the stroke of the hydraulic piston, and also the balancingforce obtained by means of my in-" vention. Figs. 7 and 8 represent details on a larger scale. Each is a central vertical section.

Similar letters of reference indicate corresponding parts in all the figures where they appear.

A is the passenger-car; B, that portion of the hoist-rope which extends from the car up to the pulley O, and B is the portion of the hoist-rope which extends downward from said pulley to the operating mechanism, which is at a low point in the building. This latter extent of the rope being always uniform is a constant weight and balances a corresponding portion of the weight of the car. tion B on the other side of the pulley G is the variable element which requires to be balanced.

D is the hydraulic cylinder. It is of ordinary dimensions and acts in the usual manner, except that the end which has heretofore been practically open is closed and is provided with a stuffing-box through which the piston-rod moves.

E is a series of grooved pulleys running on a fixed pin E, and Fis a corresponding series of grooved pulleys running on a movable pin F, which is carried by the piston-rod G, fixed to the piston G. The piston is as usual in this class of apparatus operated to hoist the car by being forced outward or to the left by water admitted through the aperture at from a source not shown, and is released and allowed to be returned by the unbalanced portion of the weight of the car and its contents by allowing the water to escape through the same aperture, all of which, and the controlling-valve and means for operating such valve by the attendant in the car, may be of any ordinary or suitable character.

M is a counterbalance-rope attached to the car A and extending up therefrom over a The porsuitable pulley C, and M the portion of such rope which is on the other side of such pulley and carries a counterbalance-weight P. This counterbalance -weight performs its usual function, and the rope M M serves in all respects in the usual manner, except as the variable weight of the two parts M M of the counterbalance-rope is affected by the compression and dilation of the air in the operating-cylinder, as will presently appear.

D is an air-chamber communicating with the interior of the cylinder D at the point represented, and which may be of larger or smaller dimensions to increase or diminish the volume of air which is imprisoned in the cylinder, and is alternately compressed and attenuated as the piston G is forced by the water in the ordinary manner toward the left and returned toward the right end of the cylinder D. Y I connect to the bottom of the inder near the left extremity a discharge-pipe H, which leads to an air-trap I, which latter it will be understood may be f any ordinary 9! suitable character adapted to discharge water and retain air. Any leakage of the water past the piston G is delivered through this pipe H into the trap I and discharged therefrom to prevent an undue accumulation. l

H is a continuation of the pipe H, and delivers through a relief or loaded check-valve J, which is operated by a helical spring inclosed in the upright portion J Its tension y be adjuste y n ng a and-Whee ,K, which operates a screw. (Not shown.) Any water in the cy inde s de ered hrou h the trapIirrespectiveofthetension. Compressed air may be elivered thr ugh the GllQf-Ycll fi J, but only when its tension rises to a high p e c n nuat H of the pipe ole livers such air at the rare intervals when the tension is exceeded. I provide a drip-cup L and draining means for discharging any Water which may through any chance be delivered with such air.

W is a check-valve, which performs the ordinary functi s o a l w g Wat r or air to pass it freely in the direction to be discharged from the cylinder D, but closes'promptly and forbids any return of air when a partial vacuum is formed in the cylinder.

The relief-valve J se es o establish an m in in n a jus abl l mi of the p essur of fluid of any kind which is allowed to es: cape. The disk J is held down by a spring J which abuts under the screw J Turning this ew ncreases o d m shes he m nimum pressure under which either air or water will be discharged.

The air-trap I operates in thelong approved manner, which may be describedbriefly, as follows: The body of the trap is always parial y filled with W ter, nd the rema nde with a he hig p e su obtaini g in the ir de So long a o y hit c mes e large open-topped vessel X inclosed in the rap i mpty a d floatsho si ng its atta h valve X tightly up against its seat, near the top of the interior Any water coming descendsthrough the orifice i and gradually fills the vessel When sufficiently loaded with water the vessel'X sinks and opens the valve X. This valve allows the water to escape through the pipe I, which extends down around the valve-stem of cuneiform section within the vessel X, and to holed away through the pipe 1 Then a sufficient quantity of the water has escaped, the vessel X again rises and closes the valve X, and the trap remains as before, holding the contents of the trap by the valve X until sufficient watcr is again received to induce another discharge. A valve 1 is provided to serve as a by-pass to allowthe air to blow out when such eti'ect is desired at any time. The checkvalve serves to prevent any flow of air or water into the cylinder D from this source. It contains the usual light disk W, equipped with a seating-ring of rubber. Itallows the flow of air and of water, when any water is present, outward from the cylinder D, controlled only by the relief-valve J and the trap I, but when under any condition air or water seeks to flow in the opposite direction this cheel r-valve W closes tightly and arrests it.

When the car i in s l w s po as show 'in Fis- 3, h portion B of o h rope extends between the extreme points of avel, and, as umin t w gh t e a c esponding weight, it balances the one hundred an fty pou ds of ho pe out o h shaft. The counterbalance-rope M also extends between the extreme points of travel, and, assuming the weight at one hundred and fifty pound i prevents t e car be g onntorbn sno d to wi in e hu ed n y pounds when .on this side. As the water admit ed und r p e sure o g tho p e cl forces the piston G outward, and conse quently by the movement of the pulleys F to th lof ake up mo e an m e of o ho s rop the can i lev t Fig. ishows the condition when the car is at one-third of its height. In this condition of he app ra us on hiind o a f y pounds of he hoist-r p and y p u ds of th co nterbalance-rope are on the outer side of the shaft an onev hund d pou d o s op and one hundred pounds of counterbalance-rope are on the inside of the shaft, so that the ropes balance each other. When the movement has progressed until the piston has arrived at the position shown in dotted lines in 1, ne th left end of t e yl n tho ari at IIO i s h gh st p s t o t sho in sa when in this position to within three hundred 7 pounds. My invention practically balances this change in the gravity of the rope B B by correspondingly changing the tension of the air expanded and compressed in the left end of the cylinder D and in the interior of the hollow piston-rod G and connected airchamber D. I have shown the piston-rod as hollow and perforated near the piston, so that a space in the interior of the piston-rod serves as an addition to the chamber in which the air is thus compressed at each elevation of the car. The effect of this is to attain the well-known advantages in stiffness and lightness due to the hollow'construction of the piston and to utilize the space in the interior as an addition to the space in which the air is compressed during a small portion and'expanded during a larger portion of each traverse. It is equivalent to a corresponding increase of the chamber D. The movement of the piston causes this air to be alternately expanded and compressed, its tension gradually decreasing as the piston G moves to the right and increasing as it moves to the left. D is an air-cock which may be opened and closed at will. It is evident that by admitting more or less air to be thus" imprisoned, which may be determined by opening the cock D and allowing the pressure inside to equal that of the atmosphere when the piston is held at one-third stroke or at any other de sired point in the stroke, I can make the tension, when the piston is at the extreme right, any required degree less than that of the atmosphere. I thus'admit the air with the pis ton G held near, but not exactly at one-third stroke. I thus attain a partial vacuum in the end of the cylinder, which is utilized in its effect on the piston G, which aids the water to hoist the unbalanced weight of rope when the car is at and near its lowest position, attains a neutral condition with regard to the pressure of the air when the piston has traversed about one-third of its stroke, and consequently raised the car to about one-third of the height of the well, and causes the confined air to exert a pressure somewhat above that of the atmosphere when the piston is at the extreme left and the car is at the top of its traverse, making it possible to addweights to the counterbalance to balance the ropes in this position. In other words, the force exerted by the compressed air helps to overcome the resistance caused by friction and back pressure, thus making it possible to add more counter weights to the elevator and thus to indirectly balance the rope.

The size of parts and best range of pressit res to be carried can be most readily obtained by a diagram. Under ordinary conditions an expansion curve can be obtained in which the loss from curvature and direction is but comparatively little.

. sufficiently-approximate balancing of the draulic cylinder.

By this means I attain aslight leakage at one or more points, the periods during which the pressure in the left of the cylinder D is below that of the atmosphere being much in excess of that during which the pressure is above that of the atmosphere, the balance of the leakage is certain to be inward, so that there is no necessity for ever providing for admitting air after the apparatus is once satisfactorily adjusted, but always for allowing the escape if the pressure of the air shallbecome excessive. This can be adjusted with great nicety by the relief-valve I, the tension of the spring being regulated at will by the hand-wheel K. The facility for adjusting in this manner and allowing the ready discharge of all excess above the desired tension when the piston is at the extreme left maybe preferred by many as the means of determining the proper amount of air to be retained in the cylinder. In other words, the quantity of air in the cylinder may always be correctly adjusted by letting in the air through the air-cock D when the car is at or near its lowest position, and the piston G is consequently at or near the extreme right,

and then closing the air-cock and allowing the first operation of the elevator to expel the surplus air throughthe check-valve IV and relief-valve J, and. thus to attain automatically the desired condition.

Modifications may be made by any good mechanic without departing fromthe principle or sacriticingthe advantages of the invention.

There may be any desired safety apparatus to arrest the descent of the car in case of accident.

Obviously there may be the ordinary provisions of duplicating the hoist-rope to provide additional safeguards against the possibility of accident from the fracture of one.

I can make the counterbalance-rope M M somewhatlighterthan the hoist rope or ropes B B. In such case the point at which the tension of the imprisoned air shall be equal to that of the external atmosphere will be correspondingly nearer the right end of the by The cylinder might also have the piston-rod on the other side, being of the type known as a pulling-machine, or upright instead of horizontal. The air-trap or other parts might be dispensed with in certain modifications, as shown in Fig. 2; or a separate cylinder may be connected and the IIO variations in pressure effected by another piston; or, in case the friction and back-pressure on piston are slight, the variations in pressure may be obtained mainly below the atmospheric pressure.

I claim as my invention 1. In an elevator the cylinder A, having its end closed, the air-space being isolated between that end and the piston G, in combination with such piston, and with a hoist-rope B, B, and provisions for operating such piston, and with the pulleys O and E, and the counterbalance weight P and the rope M, M, and

pulley therefor, arranged as shown, so that the plenum of air during the period while the car is near the top will tend to counterbalance the friction of the machine, and that there shall be a neutral period when the piston has performed a fraction of its traverse, and that the partial vacuum during the period while the car is performing the lower portion of its traverse will tend to balance the weight of the ropes, all substantially as herein specified.

2. In an elevator the cylinderA having its ends closed so as to isolate the air between one end and the piston G, in combination with such piston and with provisions for operating the hoist rope 13,13 thereby, and with such rope and the pulleys O and E, and a suitable counterbalance weight and arope and pulley therefor and with a loaded check valveJ and closed, in combination with a check-valve adapted to allow fluid to be driven out and forbid its entrance, and a suitable hoist rope and a counterbalance weight and a rope and pulley therefor, and with a trap I arranged substantially as shown, so as to allow Water to be expelled While the air is retained and the quantity automatically adjusted, substantially as herein specified.

4. In an elevator, a cylinder having its ends closed, in combination with a check-valve J', and a load as a spring, arranged to allow the air to be driven out when the pressure attains a certain point, and forbid its entrance, and with atrap I arranged substantially as shown, so as to allow Water to be expelled While the air is retained, and a suitable hoist rope and a counterbalance Weight and a rope and pulley therefor, substantially as herein specified.

In testimony that I claim the invention above set forth I aiiix my signature in presence of two witnesses.

CHARLES R. WHITTIER.

Vitnesses:

CHARLES R. SEARLE, M. F. BOYLE. 

